Can I add a Nanny apartment to a duplex in San Jose, CA?

[Mark Vesu]

I know that San Jose, CA allows nanny apartment.  Will they allow me to build one in my duplex (2+1), legally, and rent it out?  I have more than enough space to build a 800-1000 sq ft apartment.  After space for three cars.  Appreciate your help.

[Adam Mayberry]

If you have a duplex (two legal units) you can not build a 3rd separate unit and rent it to your nanny.

You COULD possibly add another master suite to one or both units. It could have a wetbar and mini fridge (hot plate), that has entry to the yard, connected by a door (that locks both sides like a hotel) - they would have their own entry and wouldnt have to go through your space